This invention is concerned with supporting means for a baffle used to close the mould of a glassware forming machine.
In a glassware forming machine of the so-called "individual section" type, the need arises to move a mould closure member, known as a baffle, between an out-of-the-way position thereof and one or more operative positions thereof in which the baffle is in alignment with an opening at the top of a mould cavity of a mould of the machine. When the machine is carrying out the so-called press-blow process, the baffle is moved from its out-of-the-way position to a position on top of the mould in which it closes the opening of the mould cavity. Glass is then pressed upwardly against the baffle and the remainder of the mould to shape a parison which is subsequently blown to the shape of a finished glass article. The baffle is then returned to its out-of-the-way position to allow removal of the parison from the mould. When the glassware forming machine is carrying out the so-called blow-blow process, the baffle is first moved from its out-of-the-way position to a position on top of a funnel on top of the mould. The funnel serves to guide a gob of molten glass into the mould cavity and the baffle is then positioned on top of the funnel. Air is blown downwardly into the mould cavity through the baffle to force the glass downwardly in the mould into contact with a plunger therein. The baffle it then returned to its out-of-the-way position so that the funnel can be removed. The baffle is then moved out of its out-of-the-way position and positioned on top of the mould to complete the mould cavity in which the molten glass is blown into the shape of a parison. The baffle is then returned to its out-of-the-way position to allow removal of the parison from the mould for subsequent blowing into the shape of a finished glass article.
Conventional moving means for moving a baffle in an individual section type machine comprises a piston and cylinder assembly having a vertically extending piston rod which projects in both directions from the piston. One end portion of the piston rod carries a horizontally extending arm on which the baffle is supported. The other end of the piston rod carries a cam which is engaged in a spiral cam track. The arrangement is such that, when the piston and cylinder assembly is operated, the piston rod moves vertically causing the baffle to also move vertically. As this movement takes place, the cam track causes the piston rod to turn about its longitudinal axis thereby swinging the arm and the baffle about the axis. The baffle is thus moved in a movement which has a rotary component about the vertical axis of the piston rod and a linear component in a vertical direction. The rotary component moves the baffle into and out of alignment with the mould while the linear component moves the baffle towards or away from the mould.
In a typical glassware forming machine of the individual section type, the baffle is supported by supporting means therefor which comprises the aforementioned arm which is mounted for movement vertically and about a vertical axis, a support mounted on the arm, and a baffle holder mounted on the support. Typically, two or more baffles are supported by supports mounted on the same arm. The holders are formed integrally with the supports and support the baffles by means of a bayonet type fitting. The supports are typically able to move vertically relative to the arm to a small extent and are acted upon by equalising means in the form of pivotally mounted links which serve to equalise the force applied to each support when the arm is moved into an operative position thereof. Thus, when the baffles mounted on an arm seat against adjacent moulds approximately equal pressure is applied between each baffle and its associated mould. Thus the baffles are able to move to a limited extent vertically relative to the arm on which they are supported.
Because the force applied to the baffles is transmitted along a horizontally extending arm, there is a tendency in practice for the arm to bend in a vertical plane. This bending causes the baffles which are mounted at different distances from the end of the arm which is secured to the piston rod to be moved horizontally by different amounts and also vertically by different amounts. This causes baffles to wear unevenly where they contact the mould and also causes similar wear to the mould. This wear causes expensive repairs especially as both mould and baffle are provided with hard metal coats. Furthermore, misalignment of the baffle with the mould causes seams to be formed in the moulded parison. These seams are a source of weakness in the parison and in the finished glass article and lead to rejection of articles.
It is another object of the present invention to provide supporting means for a baffle in which the baffle is able to move to accommodate movements caused by bending of the arm.